`myDates` is using the hash example in this case. The when `myDates` is an array this works.

````
irb(main):027:0> ZeroFill.by_date(myDates, order: :descending)
NoMethodError: undefined method `reverse!' for #<Hash:0x007f8f50a63f38>
	from /Users/t27duck/.rbenv/versions/2.0.0-p353/lib/ruby/gems/2.0.0/gems/zero_fill-0.1.0/lib/zero_fill.rb:20:in `series_by_date'
	from /Users/t27duck/.rbenv/versions/2.0.0-p353/lib/ruby/gems/2.0.0/gems/zero_fill-0.1.0/lib/zero_fill.rb:15:in `by_date'
	from (irb):27
	from /Users/t27duck/.rbenv/versions/2.0.0-p353/bin/irb:12:in `<main>'
````